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HDU-3652-B-number

2024-07-04 21:52:23   224人阅读

B-number

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2168    Accepted Submission(s): 1165


Problem Description
A wqb-number, or B-number for short, is a non-negative integer whose decimal form contains the sub- string "13" and can be divided by 13. For example, 130 and 2613 are wqb-numbers, but 143 and 2639 are not. Your task is to calculate how many wqb-numbers from 1 to n for a given integer n.
 

Input
Process till EOF. In each line, there is one positive integer n(1 <= n <= 1000000000).
 

Output
Print each answer in a single line.
 

Sample Input
13
100
200
1000
 

Sample Output
1
1
2
2


简单的数位DP，一开始一个小地方写错了，卡了好久。
#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;
int n;
vector<int>digit;
int dp[12][10][13];
int dfs(int pos,int statu,int reminder,int done){
    if(pos==-1) return statu==2&&reminder==0;
    if(!done &&  ~dp[pos][statu][reminder]) return dp[pos][statu][reminder];
    int end = done? digit[pos]:9;
    int res = 0;

    for(int i = 0; i <= end; i++){
        int tsta = statu;
        int re = (reminder*10+i)%13;
        if(statu == 0&&i == 1)
            tsta = 1;
        if(statu == 1&&i==3)
            tsta = 2;
        if(statu == 1 && i != 1 && i != 3)
            tsta = 0;

        res += dfs(pos-1,tsta,re,done&&i==end);
    }
    if(!done)  dp[pos][statu][reminder] = res;
    return res;
}
int solve(int num){
    digit.clear();
    while(num){
        digit.push_back(num%10);
        num /= 10;
    }
    memset(dp,-1,sizeof dp);
    return dfs(digit.size()-1,0,0,1);
}
int main(){

    while(cin >> n){
        cout<<solve(n)<<endl;
    }
    return 0;
}

 


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